From 2007-2009, Nyjer Morgan was a pretty valuable player.  OK, he wasn’t valuable in the Ryan Braun or Zack Greinke sense of the word, but he got the job done.  He played good defense, he hit .290-.300, and he had lightning quick speed on the base paths.

Over those years, he had been able to parlay that speed into a BABIP around .350.  Sure, .350 is high, but for a player as fast as Morgan, it’s sustainable.  But in 2010, his BABIP dipped 50 points, causing his average to dip roughly the same amount.

So what was the cause?  It’s easy to write a sudden drop in BABIP off as bad luck, but you need to see if something else was going on.

His GB%, LD% and FB% were all in line with his career numbers.  His IFFB% doubled, which could mean that he wasn’t hitting the ball on the nose due to a mechanical flaw in his swing.  However, his Infield flies went from 2 to 4.  That’s not exactly earth shattering.

So let’s look at his plate discipline.  Below is a graph of his O-swing % and his O-Contact%.  These are the rates at which he swings at pitches outside the strike zone, and at which he makes contact with pitches outside the strike zone.

First, notice his 2010 O-Swing% spiked by almost 5%.  That’s a pretty significant change.  Along with that, he made more contact with bad pitches.  By swinging at pitches outside the strike zone, he’s not going to make as solid of contact.  So, even if his contact rate was static, his BABIP would probably be negatively affected by a 5% increase in his O-Swing%.  But he was not only swinging at more pitches outside the strike zone, but he was making contact with a higher percentage of those swings.

Now, I don’t know if these increases would be enough to account for a 50 point decrease in BABIP, but they’re certainly a factor. So, if he wants to return his batting average to .300 as a Brewer, he’s going to need to lay off of pitches outside the zone.